HT instruments SIRIUS89N - Manual (Page 122)

SIRIUS89N
EN - 120
16.10. VOLTAGE ANOMALIES (VOLTAGE S AND SURGE)
The instrument is able to record as voltage anomalies all those rms values, calculated
every 10ms, beyond the percent thresholds of Voltage Reference (Vref) set during the
programming from 3% to 30 % (with step of 1%).
The Reference must be set to:
Nominal Voltage Phase to Neutral:
for Single Phase and 4 wires three phase system
Nominal Voltage Phase to Phase: for 3 wires three phase system
Example1: Three Phase System 3 wires.
Vref = 400V, LIM+= 6%, LIM-=10% =>
High Lim = 400 x (1+6/100) = 424,0V
Low Lim = 400 x (1-10/100) = 360
Example2: Three Phase System 4 wires.
Vref = 230V, LIM+= 6%, LIM-=10% =>
High Lim = 230 x (1+6/100) = 243,08V
Low Lim = 230 x (1-10/100) = 207,0V
The Instrument will detect Voltage Anomalies if the RMS Voltage Values (calculated every
10ms) beyond the above calculated thresholds. These limits remain unchanged
throughout the recording period.
When a Voltage anomalie occurs the instrument records:
• The number corresponding to the phase where the anomaly occurred.
• The “direction” of the anomaly: “UP” and “DN” identify respectively voltage drops (sag)
and peaks (Surge).
• The date and time of the beginning of the event in the form day, month, year, hour,
minutes, seconds, hundredths of second.
• The duration of the event, in seconds with a resolution of 10ms.
• The minimum (or maximum) value of voltage during the event.
16.11. VOLTAGE AND CURRENT HARMONICS
16.11.1. Theory
Any periodical non-sine wave can be represented as a sum of sinusoidal waves having
each a frequency that corresponds to an entire multiple of the fundamental, according to
the relation:
) t sin( V V v(t)
k k
1 k
k 0
ϕ ω + + =
∑
∞
=
(1)
where:
V
0
= Average value of v(t)
V
1
= Amplitude of the fundamental of v(t)
V
k
= Amplitude of the k
th
harmonic of v(t)